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Xv Z, Chen S, Song G, Hu H, Lin S, Long Y. Biochemical, histological and transcriptomic analyses for the immunological organs provide insights into heat stress-induced disease susceptibility in Largemouth Bass. Sci Total Environ 2024; 912:168758. [PMID: 38008328 DOI: 10.1016/j.scitotenv.2023.168758] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Revised: 11/19/2023] [Accepted: 11/19/2023] [Indexed: 11/28/2023]
Abstract
Aquaculture of Largemouth Bass (LMB, Micropterus salmoides), an economically important species, is badly affected by the outbreak of bacterial diseases in summer. However, the mechanisms underlying heat-induced disease susceptibility remain largely unknown. In this study, after exposure to 34 °C for 1, 7 and 14 d, the head kidney, spleen and blood of LMB were sampled for biochemical and histological assays to explore the effects of heat exposure on the oxidative and immunological indices. Compared to the controls maintained at 28 °C, chronic heat exposure (34 °C for 14 d) induced oxidative stress, caused cell apoptosis and decreased expression of the immunological genes in the head kidney and spleen tissues; and attenuated the blood immunological indices. Consistent with the impaired immunological functions, chronic heat exposure predisposed LMB to Aeromonas hydrophila infection and significantly (p < 0.001) increased tissue bacterial load. Furthermore, the effects of chronic heat exposure (heat), A. hydrophila infection (infection) and heat exposure followed by A. hydrophila infection (heat + infection) on gene expression in the head kidney and spleen of LMB were characterized by RNA sequencing. The results indicated that chronic heat exposure facilitated the bacteria-elicited changes in expression of the genes involved in a couple of metabolic and signaling pathways in both tissues. Upon heat + infection, the pathways involved in energy production and nutrients biosynthesis were enhanced, whereas those associated with the host cell functions such as cell-cell interactions and cell signaling were depressed. Our data provide new insights into the mechanisms underlying heat-induced disease susceptibility in LMB.
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Affiliation(s)
- Zhicheng Xv
- Key Laboratory of Breeding Biotechnology and Sustainable Aquaculture, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China; College of Fisheries, Southwest University, Chongqing 400715, China
| | - Shaoxiong Chen
- Key Laboratory of Breeding Biotechnology and Sustainable Aquaculture, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China; College of Fisheries and Life Science, Dalian Ocean University, Dalian 116023, China
| | - Guili Song
- Key Laboratory of Breeding Biotechnology and Sustainable Aquaculture, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China
| | - Han Hu
- Key Laboratory of Breeding Biotechnology and Sustainable Aquaculture, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China; College of Fisheries, Southwest University, Chongqing 400715, China
| | - Shimei Lin
- College of Fisheries, Southwest University, Chongqing 400715, China
| | - Yong Long
- Key Laboratory of Breeding Biotechnology and Sustainable Aquaculture, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China.
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Sheehy A, Shahin K, Camus A, Francis-Floyd R, Yanong R, Fogelson S, Soto E. Diagnosis of piscine francisellosis in Largemouth Bass from a public display exhibit in north-central Florida, USA. J Aquat Anim Health 2023; 35:201-210. [PMID: 37965692 DOI: 10.1002/aah.10197] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2023] [Revised: 07/19/2023] [Accepted: 07/31/2023] [Indexed: 11/16/2023]
Abstract
OBJECTIVE The Largemouth Bass Micropterus salmoides is an important freshwater fish that is native to the southeastern United States and is cultured for conservation, food, and for the sports fishing industry. Francisella orientalis is a globally distributed bacterial pathogen of warmwater fish species and is associated with granulomatous inflammation and high mortalities. Outbreaks of piscine francisellosis in the United States have been reported in only a few fish species. This study describes three case presentations of francisellosis in Largemouth Bass from a public display system in north-central Florida. Additionally, laboratory-controlled immersion challenges using an F. orientalis isolate from tilapia Oreochromis spp. evaluate susceptibility of Largemouth Bass fingerlings to F. orientalis infection and mortality through this exposure route. METHODS Necropsy, histologic examination, immunohistochemistry, bacterial recovery and culture, and quantitative polymerase chain reaction were used as diagnostic tools to evaluate both the affected display fish and the immersion-challenged fingerlings. RESULT Although the display fish and immersion-challenged fingerlings presented with nonspecific clinical signs, gross and histological changes were indicative of granulomatous disease. Immunohistochemical and molecular testing methods confirmed F. orientalis infection in affected fish. CONCLUSION The three case presentations described here mark the first reporting of naturally occurring piscine francisellosis in Largemouth Bass that were held in a public display exhibit. Additionally, causality was proven in the Largemouth Bass fingerlings through the immersion challenges. These findings demonstrate susceptibility through immersion-based exposure and assert that francisellosis should be considered among the list of differential diagnoses for Largemouth Bass with granulomatous disease.
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Affiliation(s)
- Amanda Sheehy
- Aquatic Animal Health Program, Department of Large Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, Gainesville, Florida, USA
| | - Khalid Shahin
- Aquatic Animal Diseases Laboratory, National Institute of Oceanography and Fisheries, Cairo, Egypt
- Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California-Davis, Davis, USA
| | - Alvin Camus
- Department of Pathology, College of Veterinary Medicine, University of Georgia, Athens, Georgia, USA
| | - Ruth Francis-Floyd
- Department of Large Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, Gainesville, Florida, USA
| | - Roy Yanong
- Tropical Aquaculture Laboratory, Program in Fisheries and Aquatic Sciences, School of Forest, Fisheries, and Geomatics Sciences, Institute of Food and Agricultural Sciences, University of Florida, Ruskin, Florida, USA
| | | | - Esteban Soto
- Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California-Davis, Davis, USA
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Seymour RD, Drenner RW, Chumchal MM. Potential Health Risks of Methylmercury Contamination to Largemouth Bass in the Southeastern United States. Environ Toxicol Chem 2023. [PMID: 37204218 DOI: 10.1002/etc.5675] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Widespread mercury (Hg) contamination of freshwater systems due primarily to deposition of atmospheric inorganic Hg (IHg) poses a potential threat to recreational fisheries. In aquatic ecosystems, IHg is converted by bacteria to methylmercury (MeHg), a potent toxin that bioaccumulates in consumers and biomagnifies through the food web, reaching elevated concentrations in fish. Methylmercury has concentration-dependent sublethal effects on fish, including reductions in reproductive output. In the present study, we conducted the first analysis of the potential health risks of MeHg contamination to largemouth bass (Micropterus salmoides), a popular gamefish, in the southeastern United States. To assess the potential health risk posed by MeHg to largemouth bass, we compared MeHg concentrations in three sizes of adult largemouth bass to benchmarks associated with the onset of adverse health effects in fish. We also determined how the risk posed by MeHg to largemouth bass varied spatially throughout the southeastern United States. Our study suggests that in the southeastern United States, MeHg poses a potential risk to largemouth bass health and that MeHg contamination may be detrimental to the fisheries of this economically important species of gamefish.
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Affiliation(s)
- Ryan D Seymour
- Biology Department, Texas Christian University, Fort Worth, Texas, USA
| | - Ray W Drenner
- Biology Department, Texas Christian University, Fort Worth, Texas, USA
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Davis BE, Cocherell DE, Sommer T, Baxter RD, Hung TC, Todgham AE, Fangue NA. Sensitivities of an endemic, endangered California smelt and two non-native fishes to serial increases in temperature and salinity: implications for shifting community structure with climate change. Conserv Physiol 2019; 7:coy076. [PMID: 30842886 PMCID: PMC6387996 DOI: 10.1093/conphys/coy076] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/25/2018] [Revised: 11/29/2018] [Accepted: 12/18/2018] [Indexed: 06/09/2023]
Abstract
In many aquatic systems, native fishes are in decline and the factors responsible are often elusive. In the San Francisco Estuary (SFE) in California, interactions among native and non-native species are key factors contributing to the decline in abundance of endemic, endangered Delta Smelt (Hypomesus transpacificus). Climate change and drought-related stressors are further exacerbating declines. To assess how multiple environmental changes affect the physiology of native Delta Smelt and non-native Mississippi Silverside (Menidia beryllina) and Largemouth Bass (Micropterus salmoides), fishes were exposed to serial exposures of a single stressor (elevated temperature or salinity) followed by two stressors (elevated temperature and salinity) to determine how a single stressor affects the capacity to cope with the addition of a second stressor. Critical thermal maximum (CTMax; a measure of upper temperature tolerance) was determined after 0, 2, 4 and 7 days following single and multiple stressors of elevated temperature (16°C vs. 20°C) and salinity (2.4 vs. 8-12 ppt, depending on species). Under control conditions, non-native fishes had significantly higher CTMax than the native Delta Smelt. An initial temperature or salinity stressor did not negatively affect the ability of any species to tolerate a subsequent multiple stressor. While elevated salinity had little effect on CTMax, a 4°C increase in temperature increased CTMax. Bass experienced an additive effect of increased temperature and salinity on CTMax, such that CTMax further increased under multiple stressors. In addition, Bass demonstrated physiological sensitivity to multiple stressors demonstrated by changes in hematocrit and plasma osmolality, whereas the physiology of Silversides remained unaffected. Non-native Bass and Mississippi Silversides showed consistently higher thermal tolerance limits than the native Delta Smelt, supporting their abundance in warmer SFE habitats. Continued increases in SFE water temperatures predicted with climate change may further impact endangered Delta Smelt populations directly if habitat temperatures exceed thermal limits.
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Affiliation(s)
- Brittany E Davis
- Department of Wildlife, Fish and Conservation Biology, University of California Davis, Davis, CA, USA
- Department of Animal Sciences, University of California Davis, Davis, CA, USA
- California Department of Water Resources, Division of Environmental Services, PO Box 942836, Sacramento, CA, USA
| | - Dennis E Cocherell
- Department of Wildlife, Fish and Conservation Biology, University of California Davis, Davis, CA, USA
| | - Ted Sommer
- California Department of Water Resources, Division of Environmental Services, PO Box 942836, Sacramento, CA, USA
| | - Randall D Baxter
- California Department of Fish and Wildlife, Bay-Delta Region 3, 2109 Arch-Airport Rd., Suite 100, Stockton, CA, USA
| | - Tien-Chieh Hung
- Department of Biological and Agricultural Engineering, University of California, Davis, CA, USA
| | - Anne E Todgham
- Department of Animal Sciences, University of California Davis, Davis, CA, USA
| | - Nann A Fangue
- Department of Wildlife, Fish and Conservation Biology, University of California Davis, Davis, CA, USA
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Lemly AD. Selenium poisoning of fish by coal ash wastewater in Herrington Lake, Kentucky. Ecotoxicol Environ Saf 2018; 150:49-53. [PMID: 29268114 DOI: 10.1016/j.ecoenv.2017.12.013] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Revised: 12/07/2017] [Accepted: 12/08/2017] [Indexed: 06/07/2023]
Abstract
Selenium pollution from the E.W. Brown Electric Generating Station was investigated in Herrington Lake, KY. Coal ash wastewater is discharged as surface water overflow from ash disposal ponds into the lake via a National Pollutant Discharge Elimination System permit issued by the Kentucky Division of Water, but the permit does not restrict or limit the amount of selenium released. Unpermitted discharges occur from seeps and drainage through leaks in ash pond dams. Together, these discharges have resulted in selenium concentrations in water, sediment, benthic macroinvertebrates, and fish that are 2-9 times the level that is toxic for fish reproduction and survival. A large proportion (12.2%, or 25 times background) of juvenile largemouth bass (Micropterus salmoides, the only species examined) exhibited spinal and/or craniofacial malformations that are consistent with selenium poisoning. Teratogenic Deformity Index values indicated a 3.05% population-level impact on the bass fishery, with total selenium-induced mortality (including pre-swimup mortality) estimated to be in excess of 25% per year. These findings confirm that coal ash discharges into Herrington Lake are contributing selenium to the Lake that is poisoning fish.
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